Honing mandrel



Dec. 28, 1965 J. SUNNEN 3,225,496

HONING MANDREL Filed sept. 17, 1962 2 Sheets-Sheet 1 J. SUNNEN HONING MANDREL Dec. 28, 1965 2 Sheets-Sheet 2 Filed Sept. 17, 1962 FIGJS FlG.l5

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United States Patent O 3,225,496 HONENG MANDREL Joseph Sonnen, 406 S. Warson Road, Clayton 5, Mo. Filed Sept. 17, 1962, Ser. No. 224,032 18 Claims. (Cl. 51-355) The present invention relates generally to honing mandrels and more particularly to honing mandrels for honing in relatively small diameter bores.

Many different kinds and forms of honing mandrels have been devised and are being used. All of the known mandrels however, have been constructed for honing in relatively large diameter bores, and accordingly all of the known constructions have been made of correspondingly large components. Furthermore, all of the known mandrels have included relatively complicated mechanisms for adjusting and supporting the honing elements.

The present invention on the other hand teaches the construction and operation of a honing mandrel which can be made in extremely small sizes heretofore unavailable, which mandrel is particularly well suited for use in bores ranging downwardly in diameter from approximately a tenth of an inch and even less. Furthermore, the present mandrel construction is extremely simple in construction and is designed to be used on existing honing machines to extend the range of use thereof.

The subject honing mandrel comprises a tubular member having an opening through one side at an intermediate location and an outwardly extending portion located on the opposite side of the tubular member from said opening forming a bearing surface for engaging a bore to be honed, a stone assembly radially movable in the opening including an abrasive element positioned extending outwardly from the opening and a backing member having a longitudinally tapered inner surface positioned extending inwardly from said opening, means for adjusting the radial position of the stone assembly in the opening including a rod slidably positioned in and supported by the tubular member and having a tapered end portion slidably engageable with the tapered inner surface of the backing member whereby longitudinal movement of said rod in the tubular member produces radial movement of the stone assembly in the side opening, and means for rotating said tubular member.

It is a main object of the present invention to provide a honing mandrel that is particularly suited for honing in relatively small diameter bores and the like.

Another object is to provide a relatively inexpensive honing mandrel.

Another object is to extend the range of bore sizes that can be honed.

Another object is to provide a mandrel for honing in small sized bores that can be employed on existing honing machines.

Another object is to simplify the construction and reduce the number of parts in a honing mandrel.

Another object is to provide a mandrel of tubular construction.

Another object is to provide means for circulating lubricant in small diameter bores during honing thereof.

Another object is to simplify the installation and adjustment of stone assemblies employed on honing mandrels.

Another object is to provide improved support means for stone assemblies employed on honing mandrels.

These and other objects and advantages of the present device will become apparent after considering the following detailed specification of a preferred embodiment in conjunction with the accompanying drawings, wherein:

FIG. l is an enlarged side elevational view of a honing mandrel assembled and constructed according to the present invention;

Patented Dec. 28, 1965 ICC FIG. 2 is a top view of the same mandrel;

FIG. 3 is `a cross-sectional View taken on line 3-3 of FIG. 2;

FIG. 4 is a further enlarged cross-sectional view taken on line 4 4 of FIG. 3;

FIG. 5 is an enlarged cross-sectional View taken on line 5--5 of FIG. 3;

FIGS. 6, y7 and 8 are side Views respectively, of the mandrel, the stone assembly, and the wedge assembly portions of the subject honing mandrel;

FIG. 9 is a top plan view of the wedge assembly of FIG. 8;

FIG. 10 is an enlarged fragmentary cross-sectional View showing a modified form of the stone assembly portion installed on the subject mandrel;

FIG. 11 is a top plan view similar to FIG. 2 showing a modified form of mandrel;

FIG. 12 is an enlarged cross-sectional view taken on line 12-12 of FIG. 11;

FIG. 13 is an enlarged cross-sectional view similar to FIG. 12 but showing yet another modified form of mandrel; and

FIGS. 14 and 15 are enlarged fragmentary top plan views similar to FIG. 11 showing other modified forms of the subject mandrel.

Referring to the drawings by reference numbers, number 10 refers generally to a honing mandrel constructed according to the present invention. The mandrel 10 includes a mandrel portion made up of a tubular holder 12 and a tubular barrel 14 mounted extending axially from one end of the holder 12. The holder 12 has a longitudinal bore 16 that extends most of its length and a connecting smaller diameter bore 18 in which the barrel 14 is positioned. The barrel 14 has a cylindrical bore 20 therethrough and the end portion of the barrel 14 positioned in the bore 18 is cylindrical .in shape. When assembled the bores 16, 18 and 20 are coaxial.

VA rectangular opening 22 is formed in the tubular barrel 14 at an intermediate location and receives a stone assembly 24 which will be described hereinafter.

The barrel 14 is cylindrical ,in the area of the opening 22 and the rest of the barrel except for the portion which fits into the bore 18 is cut away on the side substantially opposite from the opening 22. The outline of the cut away portion is clearly shown in the cross-sectional views of FIGS. 4 and 5 and is identified by the number 26. It should be noted in connection with these cross-sections that the cut away 26 is not orientated symmetrically opposite from the opening 22 but instead is offset slightly. ln practice the offset has been about '7 to the side indicatedin FIG. 4 for a mandrel designed to rotate in a counterclockwise direction. The reason for the offset is to improve the honing characteristics of the mandrel and particularly its ability to produce a round hole. It has been found in practice that a symmetrical hone, that is one in which the stone and bearing surface or shoe are directly opposite, chatters and produces holes that are not round. The -cylindrical portion of the barrel 14 in the area of the opening 22 forms a bearing surface or shoe 28 which engages a bore during honing to provide sup-port and backing for the abrasive member.

The stone assembly 24 is radially movable in the opening 22 and includes an abrasive element 30 mounted on and glued or otherwise attached to a backing member or stone holder 32. The abrasive element 30 and the stone holder 32 have la -size and shape to slidably engage the walls of the opening 22. The stone holder 32 also has a longitudinally tapered inner surface 34 as clearly shown in FIGS. 3 and 7.

A Wedge assembly 36 is slidably positioned in the holder 12 and the barrel 14. The assembly 36 includes a cylindrical portion 38 that slides in the bore 16 in the holder 12, and an endwardly extending rod portion 40 that slides in the bore 20 of the barrel 14. The free end of the rod portion 40 is tapered at 42 and has a tapered surface 44 that slidably cooperates with the tapered inner surface 34 of the stone holder 32 as shown in FIG. 3. In order to keep the tapered surfaces 34 and 44 in surface to surface engagement and thereby provide rm backing support for the stone assembly 24, a radial stud 46 is mounted on one side of the wedge portion 3S and slidably cooperates with a longitudinal slot 48 formed in the holder 12. The wedge assembly 36 is also provided with operator means indicated generally by 49 in FIGS. 8 and 9 that cooperate with adjustment means n existing honing machines to control the position thereof in the mandrel. The size of the holder 12 is also made to tit existing honing machines.

It should be apparent that longitudinal movement of the wedge assembly 36 in the mandrel 10 will cause the stone assembly 24 either to move radially outwardly in the barrel opening 22 or permit it to be moved inwardly into said opening 22. Furthermore, by having the rod portion 40 approximately equal in diameter to the diameter of the bore 20 in the barrel 14, iirm backing will be provided for the stone assembly 24 and to a large extent looseness and vibration will be eliminated.

The subject mandrel is particularly designed to provide means for honing and finishing bores of relatively small sizes in the range of a tenth of an inch and less. In this range the stone assemblies 24 are relatively small and lightweight and are positioned fairly close to the axis of the barrel 14 where little if any centrifugal force acts on the assemblies to try to throw them out of the barrel. In actual practice it has been found that by making the ystone assembly 24 closely t, or even frictionally tit, the opening 22 there is little or no tendency for the stone assembly to y out of the mandrel even when operating at fairly high speeds and not positioned in a bore. Also by making the openings and the stone assemblies as accurate as possible, any tendency for the stone assemblies to tilt or cock in the openings is greatly reduced or eliminated.

There are many ways that the openings 22 can be made. However, the method that has produced the most accurate and satisfactory results is to form the openings by a process known as electrical discharge machining which is in the nature of electrical etching or hobbing. The process employed to form the openings 22 includes the steps of immersing the tubular member 14 in an oil or dielectric coolant and while immersed moving an energized electrode toward the member 14 in the area where the opening is to be formed. Openings can be made with extreme accuracy by this process. It is also contemplated to case harden the member 14 to improve its strength and wear characteristics and particularly to increase the wear life of the bearing surface 28.

In FIG. l0 there is shown a modified stone assembly 24a. The modified assembly 24a has an abrasive element 30a glued or otherwise attached to a stone holder 32a. The stone holder 32a differs from the stone holder 32 because it has an endwardly projecting portion 33a on one end thereof. When the assembly 24a is mounted in a mandrel the Iportion 33a extends beyond one end of the opening 22 into the tubular member 14 and helps prevent the assembly 24a from flying out of the member 14. The portion 33a is shown located on the larger and heavier end of the stone assembly.` In some situations, however, it may be even more desirable to locate it on the opposite end. It has not been found absolutely necessary to even include a portion 33a on the stone holder. However, because the portion 33a does not add substantially to the cost of the assembly, in most cases such a portion is included for safety reasons.

Another modified form of mandrel b is shown in FIG. 11. The modified mandrel 10b has an opening 22b which is substantially rectangular inshape but has a projection 50b on one side. The projection 50b is normally only a few thousandths of an inch thick circumferentially and therefore di'lcult to see. For this reason it is shown in the drawings in exaggerated condition for illustrative punposes. The stone assembly 2411 ts between the projection Sb and the opposite side of the opening 22b. The opposite side of the opening 22b from the projection 50h is the side that provides most of the support for the stone assembly during a honing operation, and therefore there is no loss of support for the stone assembly by providing the projection 50h. The purpose of the projection 50]; is to reduce the area of the opening that has to be made to exacting tolerances without sacrificing any of the benefits otherwise obtainable. Furthermore, by reducing the area of the opening that has to be accurately controlled the cost of manufacturing the mandrels is reduced. At the same time the projection 50h makes it easier to slide the stone assembly into and out of the opening 22b because the opening, except for the controlled area at the projection, is wider than the stone assembly.

It is also contemplated to construct the projections 50b even wider than shown and to provide mating notches in the stone assemblies which slidably cooperate with the projections see for examples FIGS. 14 and 15. If cooperating notches and projections are provided an additional advantage is obtained in that the stone assemblies cannot then be accidentally installed backwards. In the small sizes of the stone assemblies employed on the present mandrels this can be an important advantage. In such constructions the locations of the notches and projections can also be reversed as illustrated in the drawings without changing the nature of the invention.

In FIGS. 12 and 13 are shown other modified forms of the subject mandrel. In the modified construction of FIG. 12, one side of the tubular member 14b has a flat portion 54. The flat portion 54 is formed at an angle of approximately 7 relative to a centerline through the center of the stone assembly, the centerline through the stone assembly 24b being parallel to the rightside line of the 7 angle shown therein. This is done to assure the most desirable operating relationship between the stone assembly 24h and the shoe 28h for the reasons discussed above. The purpose of the flat 54 is to provide means for circulating lubricant in a bore during honing.

The modied mandrel of FIG. 13 is similar to FIG. 12 but in addition has a second at portion 56 on the opposite side of the mandrel from the at 54. Both flat portions 54 and 56 are at an angle of approximately 7 to the stone assembly and the double flat provides even greater means for circulating lubricant during honing.

Thus there has been shown and described a novel honing mandrel construction which is particularly adapted :for honing in small size bores and which fulfills all of the objects and advantages sought therefor. It is anticipated however, that many changes, modifications variations and other uses for the subject invention will become apparent to those skilled in the art after considering this specification and the accompanying drawing. All such changes, modifications, variations and other uses which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only to the claims which follow.

What is claimed is:

1. A honing mandrel comprising a tubular member adapted to be moved into a bore to be honed, an elongated opening through one side of said tubular member and a single outwardly extending portion located on the opposite side thereof from said opening with a bearing surface thereon for engaging a bore during honing, the outermost portion of the bearing surface and the center of said opening being positioned less than apart around the tubular member, an abrasive assembly positioned in the opening and including an outer abrasive surface for engaging a bore and an inner backing portion with an inner surface positioned inside the tubular member, said inner surface being tapered longitudinally, and means including an adjustment member having a tapered surface slidably engageable with said tapered inner backing surface along the length thereof and longitudinally movable in said tubular member for radially positioning the abrasive assembly in said opening.

2. A honing mandrel comprising a tubular body having an elongated cylindrical passage therethrough and an elongated opening through one side of said body at an intermediate location, said opening being defined by parallel side and parallel end surfaces, an integral elongated outwardly extending body portion on the opposite side thereof from the opening for slidably engaging a surface being honed, said outwardly extending body portion having an elongated outermost portion circumferentially oriented nearer to one side of the opening than to the other, an abrasive assembly having parallel side and parallel end surfaces slidably engageable with corresponding surfaces of said opening, said abrasive assembly having a longitudinallyinclined inner surface positioned inside the cylindrical passage, and adjustment means including a member longitudinally slidable in said body passage and engageable with said inclined surface to radially adjust the position of said assembly in said opening, said adjustment means including a rod having a diameter substantially the same as the diameter of the passage and a tapered end `portion slidably engageable with the inclined inner surface of the assembly to provide support therefor along substantially the full length thereof.

3. The honing mandrel defined in claim 2 wherein said adjustment means and said tubular body have cooperating relatively movable means to prevent relatively rotational movement therebetween.

4. A honing mandrel comprising a tubular body adapted to be installed on a honing machine, a longitudinal passage through said body, a tubular member attached to said body at one end thereof and having a cylindrical passage therethrough axially aligned with the body passage, a substantially rectangular opening through one side of the tubular member at an intermediate location, a stone assembly of similar rectangular cross section positioned in said opening and radially movable therein, said assembly having an outer abrasive surface for engaging a surface to be honed and a backing portion having a longitudinally tapering inner surface positioned inside said tubular member, means slidably engageable with said tapered inner surface for radially positioning the stone assembly in the opening, said last named means including a rod member of substantially the same diameter as the diameter of the cylindrical passage, said rod member having a tapered end portion slidably engageable with the tapered inner surface of the stone assembly, and means on said rod member for predetermined positive operative engagement with adjustment means on a honing machine.

5. The honing mandrel defined in claim 4 wherein said tubular member has an integral outwardly extending portion located substantially opposite from the rectangular opening, said portion having an elongated bearing surface the radial outermost portion of which is oriented to engage a bore to be honed at a location thereon that is closer to the stone assembly circumferentially in one direction than the other.

6. The honing mandrel defined in claim 4 wherein said stone assembly has a projection on one end thereof which extends endwardly beyond the opening into the cylindrical body passage in the tubular member when the stone assembly is positioned in said opening.

7. A honing mandrel comprising a tubular member having a longitudinal passage therethrough, an opening through one side of the tubular member into the passage,

a stone assembly of substantially the same cross sectional size and shape as the opening radially slidably positioned in the opening, said stone assembly including an abrasive outer surface and an inner backing portion extending into the passage in the tubular member, said backing portion having an inner surface inclined longitudinally relative to the axis of the passage, a rod member slidably positioned in said passage, said rod member having a diameter substantially the same as the diameter of the passage and an inclined end portion slidably engageable with the inclined inner surface of the stone assembly backing portion, said rod member being movable longitudinally in said passage to radially position the stone assembly in the opening and means on one end of the stone assembly engageable with the tubular member to limit radial outward movement thereof.

8. The honing mandrel defined in claim 7 wherein said tubular member has an outwardly extending portion with a bearing surface thereon, said bearing surface being shaped and located to engage a surface being honed approximately 173 circu-mferentially from the center of the stone assembly.

9. The mandrel defined in claim 8 wherein the tubular member has an outer surface portion extending between the opening and the bearing surface that is shaped to define a longitudinal lubricating passage between said member and a bore being honed.

16. A honing mandrel comprising a body portion adapted to be rotatably installed on existing honing machines, a tubular member attached to the body portion for rotation therewith, said tubular member having a longitudinal cylindrical bore therethrough and an opening into said bore at an intermediate location, an enlarged portion on said tubular member extending radially outwardly thereon substantially opposite said opening, said enlarged portion having a single outer bearing surface for slidably engaging a surface to be honed, the radial outermost portion of said bearing surface and the center of said opening being circu-mferentially spaced on the tubular member by an angle less than an abrasive assembly including an abrasive member mounted on a backing member radially slidably positioned in the opening in the tubular member, said backing member having a longitudinally tapering inner surface, and an adjustment member having means thereon for predetermined positive operative connection with means on a honing machine, said adjustment member being slidably positioned in the tubular member and having a tapered portion slidably engaging the tapering inner surface of the backing member to change the radial position of the abrasive assembly in the opening during longitudinal movement thereof.

11. The honing mandrel defined in claim 10 wherein said opening in the tubular member and said backing member have opposed mating relatively slidable accurately formed edge portions only one of the edge portions of the opening being in surface to surface contact with the corresponding edge portion of the backing member along substantially the full length thereof.

12. The honing mandrel defined in claim 11 wherein said mating accurately formed edge portions include a projection and a surface slidably engageable therewith.

13. The honing mandrel defined in claim 11 wherein said mating accurately formed edge portions include a projection and a notch for slidably receiving said projection.

14. The honing mandrel defined in claim 10 wherein the tubular member has a longitudinal portion removed from the outer surface thereof in the area between the opening and the enlarged portion, said removed portion forming a passage with a bore being honed for coolant flow.

15'. The honing mandrel defined in claim 10 wherein the tubular member has a longitudinal portion removed from both opposite sides thereof in the areas between the opening and the enlarged portion, said removed portions forming passages with a bore being honed for coolant to flow along opposite sides of the mandrel during a honing operation.

16. The honing mandrel dened in claim 15 wherein said removed portions are symmetrically positioned circumferentially relative to opposite sides of the enlarged portion.

17. A honing mandrel comprising an elongated tubular member having an adapter portion mounted on one end thereof, an opening at an intermediate location through the tubular member, a honing stone assembly positioned in said opening and radially movable therein for changing the honing diameter, saidl stone assembly having an outer abrasive portion engageable with a surface to be honed and an inner backing portion on which the abrasive portion is mounted, said inner backing portion having a tapered inner surface positioned inside the tubular member, an adjustment member including a rod slidably positioned in the tubular member and including a tapered end portion which is constructed to mate in surface-tosurface engagement with the inner tapered surface of the backing portion of the stone assembly, said surface-tosurface engagement providing support for the stone assembly over substantially the full length thereof, means for maintaining the tapered end portion of the rod and the inner tapered surface of the stone assembly in mating surface-to-surface contact in all honing positions of the rod, and means integral with the tubular member on the opposite side thereof from the opening for engaging a surface to be honed at a ditferent location from the stone assembly, said last named integral means including a single outwardly extending portion defining a bearing surface located on the opposite side of the tubular member from the stone assembly the outwardmost extending portion thereof being parallel to the axis of the tubular member and located nearly opposite from the stone assembly.

18. A honing mandrel comprising a tubular member adapted to be moved into a bore to be honed, an opening through one side of said tubular member, a stone assembly of substantially the same cross sectional size and shape as the opening frictionally slidable radially in said opening, said assembly having an outer abrasive portion for engagement with a surface to be honed and an inner backing portion with a longitudinally tapered inner surface, the -mass of said stone assembly being insufficient at normal operating speeds of the mandrel to produce an outward force of sufficient magnitude to overcome the frictional engagement between the stone assembly and the opening thereby to prevent the assembly from ying out of the opening, adjust-ment means movable longitudinally in said tubular member and slidably engageable with the tapered inner surface of the stone assembly to moved said assembly radially outwardly in said opening to maintain the abrasive portion of the assembly engaged with a bore being honed, and cooperating relatively movable means on the adjustment means and on the tubular member to prevent relative rotational movement therebetween, said tubular member having an integral outwardly extending portion with a bearing surface thereon, the outermost portion of which is located to engage a bore being honed at about 173 from the center of the opening.

References Cited by the Examiner UNITED STATES PATENTS 1,989,831 2/1935 Sunnen 51-l84.3 2,309,485 1/1943 Wallace 51-184.3 2,354,890 8/ 1944 Stoples 5 1-1 84.3 2,376,851 5/ 1945 Sunnen 51-l84.3 2,412,419 12/ 1946 Palotsee 51-1 84.3 2,532,682 12/1950 Sunnen 5l--l84.3 2,787,097 4/1957 Heath 51-184.3 3,011,367 12/1961 Tilden 76-108 3,037,333 6/1962 Stelmachowski 5l-184.3 3,053,118 9/1962 Lavallee 76-108 3,060,648 10/1962 Gjertsen 5l-l84.3 3,075,323 1/1963 Weir 5l-l84.3 3,094,820 6/1963 Hannon 51-184.l1

OTHER REFERENCES Gehring: German application 1,007,655, printed May 2, 1957 (KI.67a), 2 pp. spec., l sheet drawing.

Nagel: German application 1,078,897, printed March 31, 1960 (KI.67a), 2 pp. spec., 1 sheet dwg.

ROBERT C. RIORDON, Primary Examiner.

FRANK H. BRONAUGH, I. SPENCER OVERHOL- SER, LESTER M. SWINGLE, Examiners. 

1. A HONING MANDREL COMPRISING A TUBULAR MEMBER ADAPTED TO BE MOVED INTO A BORE TO BE HONED, AN ELONGATED OPENING THROUGH ONE SIDE OF SAID TUBULAR MEMBER AND A SINGLE OUTWARDLY EXTENDING PORTION LOCATED ON THE OPPOSITE SIDE THEREOF FROM SAID OPENING WITH A BEARING SURFACE THEREON FOR ENGAGING A BORE DURING HONING, THE OUTERMOST PORTION OF THE BEARING SURFACE AND THE CENTER OF SAID OPENING BEING POSITIONED LESS THAN 180* APRT AROUND THE TUBULAR MEMBER, AN ABRASIVE ASSEMBLY POSITIONED IN THE OPENING AND INCLUDING AN OUTER ABRASIVE SURFACE FOR ENGAGING A BORE AND AN INNER BACKING PORTION WITH AN INNER SURFACE POSITIONED INSIDE THE TUBULAR MEMBER, SAID INNER SURFACE BEING TAPERED LONGITUDIANLLY, AND MEANS INCLUDING AN ADJUSTMENT MEMBER HAVING A TAPERED SURFACE SLIDABLY ENGAGEABLE WITH SAID TAPERED INNER BACKING SURFACE ALONG THE LENGTH THEREOF AND LONGITUDINALLY MOVABLE IN SAID TUBULAR MEMBER FOR RADIALLY POSITIONING THE ABRASIVE ASSEMBLY IN SAID OPENING. 